1. Technical Field
The present invention relates to a semiconductor device which includes a wire having turning pattern.
2. Related Art
Recently, there is a noticeable proliferation of various types of portable electronic apparatuses such as portable mobile information terminals. In view of technological tendencies to demand increased portability and higher performance in such electronic apparatuses, semiconductor devices packaged in these electronic apparatuses are desired to be made even smaller, lighter, and thinner. One conventional package structure (sealing structure) for semiconductor devices which addresses such tendencies and desires is a chip size package whose external size can be made almost the same as that of a semiconductor substrate (semiconductor chip) on which an integrated circuit is formed.
As electronic apparatuses are being made smaller, there are demands to integrate high-performance capacitors and inductors in semiconductor devices. Many inductors formed on semiconductor substrates have a spiral shape. The Q-value (the ratio between inductance and resistance) is one parameter which indicates the performance of an inductor.
Since the Q-value decreases when a multiple-turn inductor such as a spiral inductor is used in a semiconductor device, various types of conventional structures have been produced to counter this (e.g., see Japanese Unexamined Patent Application, First Publication No. 2000-323656 and Japanese Patent No. 3509362). In a semiconductor device described in JP 2000-323656, an insulating film, a spiral inductor, and an insulating layer are formed sequentially on a semiconductor substrate, and a soft magnetic thin-film is multilayered over the insulating film. This configuration maintains a large relative magnetic permeability and obtains high inductance.
In a semiconductor device described in JP 3509362, metal wires of a spiral inductor are provided on a plurality of polyimide resin columns formed on a semiconductor substrate. Since this obtains a hollow section between the semiconductor substrate and the spiral inductor, the relative permittivity (relative dielectric constant) is low, enhancing the characteristics of the inductor.
However, while the semiconductor device of JP 2000-323656 uses a magnetic thin-film to enhance the characteristics of the inductor, there is concern over increasing costs of this technology. While the semiconductor device of JP 3509362 enhances the inductor characteristics by arranging the spiral inductor over the resin columns, the configuration is unstable and does not easily remain strong. This makes it difficult to package the semiconductor device in external apparatuses, and, since it is also difficult to maintain long-term reliability, its application is limited.